DNA Testing in Genealogy

A genealogical DNA test looks at a person’s genetic code at specific locations. Results give information about the person’s ancestry far back in time. The tests compare the results of an individual to others from the same lineage or to current and historic ethnic groups. They do not give information on genetic diseases or disorders but are only intended to provide genealogical information.

Several DNA analysis companies provide Y-DNA and mtDNA analyses. Once you have ordered you will receive a ‘spit kit’ to collect a sample of saliva. You send your sample in the mail in the package provided. Once your sample arrives at the laboratory, scientists will determine your genetic signature across your mtDNA and Y chromosome, depending on what you have ordered. Then your results will be mailed to you.

As noted above, Y-DNA is passed on from fathers to their sons, while mothers pass on mtDNA to both their sons and daughters. But mtDNA dies with men and it survives only in the female line. This means that a man’s lineage can be followed along both paternal and maternal lines, while in a woman only her maternal or mtDNA line can be followed. However, a woman who wishes to determine her direct paternal DNA ancestry can ask a relative who shares her (maiden) surname (the same Y-DNA) to take a test for her.

Some companies also offer so-called autosomal DNA testing. Y-DNA and mtDNA testing only looks at small amounts of one’s DNA, (only one’s direct paternal or maternal lineage). On the other hand, autosomal DNA analyses the entire genome, all 23 pairs of chromosomes as opposed to only the Y chromosome or mitochondrial DNA. Without getting into too much technology, this means that it provides information on all your ancestors, not only along your father’s or mother’s line.

Note that your results will be kept confidential. However, they may be included in the database used for further research into our genetic history. In this case your sample will be identified only with a number and can never be traced back to you.